By Huw Jones and Simon Jessop LONDON (Reuters) -Leading British asset manager Aviva Investors plans to push boards for greater action on biodiversity and human rights so that companies consider “the whole picture of sustainability”. Alongside climate change, a core focus for most investors, Aviva’s move reflects growing concern over the corporate world’s impact on nature and the treatment of social stakeholders, including workers, across often lengthy supply chains. Insurance group Aviva’s asset-management arm, which handles 262 billion pounds ($354.62 billion) of assets, will now rank human r…